Suchergebnisse

12 pags., 8 figs., 1 tab. ; The structure of Ge80 has been investigated at the ISOLDE facility at CERN. A previous study reported for the first time a low-lying 02+ intruder state at 639 keV, based on the coincidence with a previously unobserved 1764-keV γ ray, and suggested it as evidence for shape coexistence in Ge80. We used the β decay from the 3- 22.4-keV state in Ga80 to enhance the population of low-spin states in Ge80, including any excited 0+ level, and γγ coincidences to investigate it. We observed a 1764-keV γ ray in coincidence with strong transitions in Ge80, thus not feeding the proposed 639-keV 02+. No connecting transitions from previously known levels to the 639-keV and 2403-keV 23+ states could be established either. Shell-model calculations for Ge isotopes and N=48 isotones were performed. They succeed to explain most of the experimental levels, but fail to reproduce the presence of a 02+ state below ≈1200 keV in Ge80. Our experimental findings and shell-model calculations are difficult to reconcile with a very low-lying 02+ state in Ge80. ; This work was supported by Spanish national projects FPA2015-65035-P, RTI2018-098868-B-I00, and PID2019- 104390GB-I00, by Grupo de Física Nuclear (GFN) at Universidad Complutense (Spain), by the U.S. DoE Grant No. DE-FG02-94ER40834, and by the German BMBF Grant 05P19PKFNA. The support by the European Union Seventh Framework through ENSAR (Contract No. 262010) and by the ISOLDE Collaboration and technical teams is acknowledged. ; Peer reviewed

4 pages, 3 figures, 1 table.-- PACS nrs.: 21.10.Tg; 23.40.−s; 27.40.+z. ; The Advanced-Time-Delayed method was used to measure lifetimes of the states in Ar-41 populated in the β decay of Cl-41. The nuclei Cl-41 were produced at ISOLDE by 1.4-GeV proton bombardment of a thick UCx target and mass-separated as molecular ions, XeCl+. Our measured half-life of the 167.1-keV state, T(1/2) = 315(15) ps, is significantly lower than the previously measured value of 410(30) ps. We have also determined T(1/2) = 260(80) ps and T(1/2) ≤ 46 ps for the 515.9- and 1867.7-keV states, respectively. These are the shortest lifetimes measured so far with the ultrafast timing method using the new LaBr3(Ce) crystals for γ-ray detection. ; This work was performed as part of an undergraduate research project (ERW) at the Physics Department of the University of Notre Dame. Fast-timing detectors and electronics were provided by the Fast Timing Pool of Electronics. This study was supported in part by the NSF PHY04-57120, Swedish Research Council, BMBF Grant No. 06KY205I, the Alexander von Humboldt Foundation (WBW), Foundation for Polish Science (AK), the European Union Sixth Framework through RII3-EURONS (Contract No. 506065), and the EURTD project TARGISOL (HPRI-CT-2001-50033). ; Peer reviewed

6 pages, 2 figures.-- PACS nrs.: 24.30.Cz, 25.70.Gh.-- Presented at the Zakopane Conference on Nuclear Physics (Zakopane, Poland, Sep. 4–10, 2006). ; The Advanced Time Delayed method has been used to measure the lifetimes of excited states in the exotic nuclei Sb-134, Sb-135 and Te-136 populated in the beta decay of Sb-134, Sb-135 and Te-136, respectively. High purity Sn beams were extracted at the ISOLDE separator using a novel production technique utilizing the molecular SnS+ beams to isolate Sn from contaminating other fission products. Among the new results we have identified the 1/2+ state in Sb-135 and its E2 transition to the lower-lying 5/2+ state was found to be surprisingly collective. This measurement represents also one of the first applications of the LaBr3 scintillator to ultra fast timing. ; This work was supported by the NSF PHY04-57120, NSF PHY-0555366, Swedish Research Council, BMBF grant 06KY205I, the Alexander von Humboldt Foundation (WBW), the European Union Sixth Framework through RII3-EURONS (contract no. 506065) and the EU-RTD project TARGISOL (HPRI-CT-2001-50033). ; Peer reviewed

10 pags., 8 figs., 1 tab.-- Open Access funded by Creative Commons Atribution Licence 4.0 ; Excited states in Sn133 were investigated through the ß decay of In133 at the ISOLDE facility. The ISOLDE Resonance Ionization Laser Ion Source (RILIS) provided isomer-selective ionization for In133, allowing us to study separately, and in detail, the ß-decay branch of In133J¿=(9/2+) ground state and its J¿=(1/2-) isomer. Thanks to the large spin difference of the two ß-decaying states of In133, it is possible to investigate separately the lower and higher spin states in the daughter, Sn133, and thus to probe independently different single-particle and single-hole levels. We report here new ¿ transitions observed in the decay of In133, including those assigned to the deexcitation of the neutron-unbound states. ; We acknowledge the support of the ISOLDE Collaboration and technical teams. This work was supported in part by the Polish National Science Center under Contract No. UMO-2015/18/E/ST2/00217 and under Contract No. UMO-2015/18/M/ST2/00523, by the Spanish MINECO via FPA2015-65035-P project, by the Portuguese FCT via CERN/FIS-NUC/0004/2015 and CERN-FIS-PAR-0005-2017 projects. The research leading to these results has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002.